[lex] Remove spurious whitespace

Author: tkoeppe

source/lex.tex

@@ -51,7 +51,7 @@
 \rSec1[lex.phases]{Phases of translation}%
 
 \pnum
-\indextext{translation!phases|(}
+\indextext{translation!phases|(}%
 The precedence among the syntax rules of translation is specified by the
 following phases.\footnote{Implementations must behave as if these separate phases
 occur, although in practice different phases might be folded together.}